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What causes heavy menstrual bleeding?

What causes heavy menstrual bleeding?

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What is heavy menstrual bleeding?

Heavy menstrual bleeding means having periods that are much heavier or longer than usual. It is sometimes called menorrhagia, although this term is used less often now. In the UK, it is one of the most common reasons people seek help from a GP about periods.

A period may be considered heavy if you need to change your pad or tampon very often, pass large blood clots, or bleed for more than seven days. It can also affect daily life, leaving you tired, anxious, or unable to carry on as normal.

Hormonal causes

One common cause is a hormonal imbalance, especially when the body does not ovulate regularly. If ovulation does not happen, the womb lining can build up and then shed more heavily. This can happen in teenagers, during perimenopause, or in people with conditions such as polycystic ovary syndrome.

Changes in oestrogen and progesterone can also affect how thick the womb lining becomes. When the lining is thicker, the period that follows may be heavier and last longer than usual.

Conditions affecting the womb

Fibroids are non-cancerous growths in the womb and are a common cause of heavy bleeding. They can make periods heavier, longer, and more painful. Some people also notice pressure in the pelvis or a need to pass urine more often.

Endometriosis and adenomyosis can also be linked to heavy periods. These conditions may cause painful periods as well as bleeding that is difficult to manage. Polyps in the womb lining can sometimes cause irregular or heavy bleeding too.

Other medical causes

Heavy bleeding can sometimes be caused by bleeding disorders, such as von Willebrand disease. These conditions affect how the blood clots and may make periods much heavier than expected. They may be more likely if heavy bleeding has been present since periods first started.

Thyroid problems can also play a part. An underactive or overactive thyroid may affect the menstrual cycle and lead to changes in bleeding patterns. Certain medicines, including blood thinners, can also make periods heavier.

When to seek help

It is a good idea to speak to a GP if your periods are affecting your quality of life. This is especially important if you feel faint, short of breath, very tired, or need to change protection very frequently. Heavy bleeding can lead to iron deficiency and anaemia.

A GP can ask about your symptoms, check for possible causes, and arrange tests if needed. Treatment depends on what is causing the bleeding, and there are often effective options to help reduce it.

Frequently Asked Questions

What causes heavy menstrual bleeding?

Heavy menstrual bleeding can be caused by hormonal imbalances, uterine fibroids, polyps, adenomyosis, bleeding disorders, thyroid problems, certain medications, and in some cases no clear cause is found.

Can hormonal changes cause heavy menstrual bleeding?

Yes. Changes in estrogen and progesterone can affect how the uterine lining builds up and sheds, which can lead to heavier periods.

Do uterine fibroids cause heavy menstrual bleeding?

Yes. Uterine fibroids are a common cause of heavy or prolonged menstrual bleeding because they can interfere with the normal contraction of the uterus and increase bleeding.

Can polyps lead to heavy periods?

Yes. Endometrial or cervical polyps can cause irregular or heavy bleeding by creating extra tissue that bleeds easily.

What is adenomyosis and can it cause heavy bleeding?

Adenomyosis happens when uterine lining tissue grows into the muscle wall of the uterus. It can cause heavy, painful, or prolonged menstrual bleeding.

Can endometriosis cause heavy menstrual bleeding?

Endometriosis more often causes pain, but some people with it also experience heavy or irregular bleeding, especially if there are related hormonal or uterine issues.

Do bleeding disorders cause heavy menstrual bleeding?

Yes. Conditions such as von Willebrand disease or other clotting problems can make it harder for blood to clot, leading to heavier periods.

Can thyroid problems lead to heavy menstrual bleeding?

Yes. An underactive or overactive thyroid can disrupt hormone balance and menstrual cycles, sometimes causing heavy bleeding.

Can polycystic ovary syndrome cause heavy periods?

PCOS can cause irregular ovulation and hormone imbalance, which may lead to unpredictable or heavy menstrual bleeding in some people.

Can a copper IUD cause heavier menstrual bleeding?

Yes. A copper IUD commonly increases menstrual flow and cramping, especially during the first months after insertion.

Can blood-thinning medicines cause heavy menstrual bleeding?

Yes. Anticoagulants and some antiplatelet medicines can make periods heavier because they reduce the blood's ability to clot.

Can uterine cancer cause heavy bleeding?

Yes. While less common, cancer of the uterus or cervix can cause abnormal or heavy menstrual bleeding and should be evaluated promptly.

Can perimenopause cause heavy menstrual bleeding?

Yes. During perimenopause, hormone levels fluctuate and ovulation may become irregular, which can make periods heavier or more unpredictable.

Can stress cause heavy menstrual bleeding?

Stress can affect hormone regulation and cycle timing, but it is usually not the only cause of heavy menstrual bleeding. Other medical causes should be considered.

Can pregnancy-related problems be mistaken for heavy periods?

Yes. Early pregnancy loss, ectopic pregnancy, or other pregnancy-related bleeding can sometimes be mistaken for a heavy menstrual period.

Can infection cause heavy menstrual bleeding?

Yes. Some infections, especially those affecting the uterus or cervix, can cause abnormal bleeding and may contribute to heavier periods.

Can obesity be linked to heavy menstrual bleeding?

Yes. Obesity can affect estrogen levels and ovulation, which may lead to abnormal or heavy menstrual bleeding.

Can diet or low iron cause heavy menstrual bleeding?

Low iron does not usually cause heavy bleeding, but heavy bleeding can lead to iron deficiency. Poor nutrition may also affect overall menstrual health in some people.

Can heavy menstrual bleeding happen without a known cause?

Yes. In many cases, no clear structural or hormonal cause is found, and the bleeding is classified as abnormal uterine bleeding without an obvious source.

When should heavy menstrual bleeding be evaluated by a doctor?

It should be evaluated if it soaks through pads or tampons quickly, lasts longer than usual, causes large clots, leads to dizziness or anemia, or interferes with daily life.

Useful Linksxxx

Useful Links : What causes heavy menstrual bleeding?
Heavy periods (menorrhagia)

NHS overview of heavy periods, including possible causes and when to seek help.
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NHS information on heavy menstrual bleeding and common causes.
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NHS inform guide to heavy menstrual bleeding, symptoms and causes.
Heavy periods

UK health charity-style information on heavy periods and possible causes.
Heavy menstrual bleeding (menorrhagia)

Women's Health Concern factsheet explaining causes and treatment options.
Heavy periods

Jo's Trust information page covering heavy periods and related causes.
Heavy periods and bleeding between periods

Cancer Research UK page on heavy periods and when bleeding may be linked to underlying conditions.
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NHS page discussing heavy periods, including possible causes and symptoms to watch for.
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This website offers general information and is not a substitute for professional advice. Always seek guidance from qualified professionals. If you have any medical concerns or need urgent help, contact a healthcare professional or emergency services immediately.

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